Switch operating mechanism



June 5, 1956 J. E. DAVIS 2,749,415

SWITCH OPERATING MECHANISM Filed Dec. 4, 1952 2- Sheets-Sheet 1 awe/whom s w 0 6 6 w w 2 3% mm 4 E 4E, m 5 n m F M A 2 4 06 4 I Z x w 6, 5 55 J M 0 6 w 4 & 6 w xw 2 g rlwsialilli.

J n 5, 1956 J. E. DAVIS 2,749,415

SWITCH OPERATING MECHANISM Filed Dec. 4, 1952 2 Sheets-Sheet; 2

PAss. HANGAR TERMINAL HANGAR O O O 0 m 0 C i H /41 26 wuwwbob FIG. 6 51 JAMES E. DAV/5 Unite 1 The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This invention relates to a switch operating mechanism especially useful to actuate a switch for a facsimile map control panel. of the type found in airport control towers.

Prior to this invention there had not been a satisfactory switch operating mechanism that is small enough to install in the members used for the operation of all electrical circuits necessary for the operation of a major airfield, due to the limited surface space available in a control tower. An object of this invention is to provide a dependable switch operating mechanism that is small enough to fulfill the above mentioned need and a switch which includes such operating mechanism in a facsimile map control panel to cause the panel to be of increased value in view of its greater capacity for handling signals.

A more specific object of the invention is to provide a switch operating mechanism that includes a push button actuated ratchet engageable successively with mechanical parts for rotating the ratchet through a sequence of positions, each position maintaining a switch operating push rod in a certain position, namely, the ratchet holding the rod in a partially depressed position in response to the initial push button actuation, and releasing the push rod in response to the next push button actuation, whereby due to other constructions, the push button will become lighted while partially depressed signaling that the switch is closed by the push rod.

A further object of the invention is to provide a control panel with switch mechanisms which are constructed in such a way that they require positive, intentional action by an individual to change their positions, and to provide switch operating mechanisms whose positions are indicated not only by touch but also by vision.

At the present time there are four methods used to control the lighting of a facsimile map control panel, each leaving much to be desired. Conventional toggle switches and/or circuit breakers are used, but they require entirely too much space. The second is the use of push button switches that remain down after being pushed, until pulled up. A push button switch of this type cannot be conveniently operated if the operator is wearing gloves, or if they are placed too close together, as at intersections of taxiways or in a series of short taxiways. Moreover if this type of switch is too close to another one, the operator cannot get his fingers between them to turn one off without affecting the other. If an object, such as a book, is placed on one of these switches it may be actuated by accident. The third panel system includes a push button leaf switch which closes a locking relay on the first depression and opens the relay on the second depression. This system is entirely too complex fro-m an electrical standpoint, the maintenance is prohibitive, and it is not dependable. Finally, a telephone dial system has been tried, and it is subject to the same difiiculties as the locking relay system. The present invention provides means tes Patent l Z,?4,4l5 Patented June 5, 1956 iCC for actuating the airport lighting from a control panel, that overcome each difficulty mentioned above and the invention is mechanically simpler than most previously tried systems.

Other objects and features of importance will become apparent in following the description of the illustrated form of the invention.

In the drawings:

Fig. l is an elevational view of the switch operating mechanism together with a subminiature switch actuated thereby.

Fig. 2 is a longitudinal sectional view of the mechanism of Fig. l, the switch being removed.

Fig. 3 is a fragmentary sectional view of the mechanism illustrating particularly, the ratchet in one position.

Fig. 4 is a fragmentary sectional view of the mechanism showing a second position of the ratchet.

Fig. 5 is a fragmentary sectional view of the mechanism showing another ratchet position.

Fig. 6 is a fragmentary sectional view of the mechanism suggesting how the mechanism may be fastened to the facsimile map control panel and showing how the push button is illuminated.

Fig. 7 is a plan view of a typical control panel with one suggested arrangement of push button switch actuating mechanisms therein.

A typical lighting facsimile map control panel 10 of the type found in an airport control tower is shown in Fig. 7, the arrangement of panel 10 being peculiar to the particular airport for which it has been constructed. A popular construction is seen in Fig. 6 where there is a light transmissive plastic base 12 having a superimposed light diffusing sheet 14 thereon, the top of which is painted as at 16 to indicate the various runways, buildings, aprons and the like (Fig. 7). A transparent protective sheet 18 of suitable material, as plastic, is usually placed on the paint 16, and due to space limitations, panel 10 may not be larger than 15 by 19 inches in planform (governed by present regulation). It is easily appreciated that space saving measures must be taken in the manufacture of such a panel, especially in view of the fact that the control tower operator must be able to operate all of the landing, signal and other lighting from such a small panel.

Accordingly, apertures 20 are provided in the panel at positions corresponding to airport lights, and each aperture has a switch operator mechanism or unit 22 therein adapted to be manually actuated by the control tower operator in the performance of his duties. Each switch operating mechanism 22 used in panel 10 may be identical in construction and as an added space saving feature, the mechanisms may be of several lengths so that when two or more units 22 are close to each other, the lower ends of each containing a subminiature switch or the like will be vertically spaced from each other. Mechanism 22 includes a casing 26, the upper end of which is externally threaded and disposed in one of the apertures 2t) so that upper and lower nuts 28 and 30 hearing on panel 10 may hold the casing 26 and all of the structure connected to it in place within the panel. Casing 26 has an open upper end and a closure 32 at its lower end on which a yielding element, as spring 34, seats. The opposite end of spring 34 bears against a push rod 36 that is mounted for re: ciprocatory motion in casing 26. Spring 34 is so selected with respect to the space it occupies between closure 32 and push rod 36, that the push rod is biased by the spring toward the open end of casing 26 in all positions of the push rod except when the push rod is in its initial position ,(FigsZandS) 3 Means are provided for depressing the push rod 36 against the yielding opposition of the spring 34, and consist of a push button 38 made of a light diffusing material, as certain plastics or glasses, so that light from the light transmissive base 12 causes the push button 38 to appear lighted. For this purpose an opening 40 is provided in the casing 26, and there is a notch 42 in the side of the push button to reflect the light ray, thereby enhancing the luminosity of the button 38. A shank 44 extends from the lower end of the push button 33 and is disposed in an upwardly opening bore 46 in push rod 36 thereby releasably retaining the push button assembled with the push rod. In this way the push button may be readily removed for replacement, this being important where color schemes are employed, for example red lights to represent barrier lights and blue lights to represent taxiways.

Attention is now invited to Figs. 3-5 where several conditions of operation are portrayed. From the initial position (Fig. 5) the button 38 is depressed, causing one jaw 50 of ratchet 52 to engage an abutment 54 in casing 22. Ratchet 52 is pivoted on a flat part of rod 36 between the ends thereof, and the abutment 54 consists of a pin extending across the casing 26 and located in a relieved portion 56 of push rod 36. There is an opening 53 in casing 26 near abutment 54 and an opening 69 in the casing directly across from opening 58, thus allowing the ratchet 52 to pivot freely. When the button 38 is released by the finger of the control tower operator spring 34 returns the push rod 36, but the jaw 62 of ratchet 52 engages an edge of the opening on preventing full return of the operator, consisting of the push button and push rod (Fig. 3). When the push rod is again depressed, the ratchet 52 has its side 64 come into contact with abutment 54 causing the ratchet 52 to rotate to the position shown in Fig. 5, whereby upon release of the push button, it and rod 36 are returned the full extent by spring 34.

Push rod 36 is of opaque material and when the push rod and button are fully extended (Fig. 2) a part of the push rod closes the opening 49 preventing any light from enter- 7 ing the push button from the base 12. Thus the button signals, by the absence of illumination, that the airport light represented by it is off. But when the ratchet 52 retains the push rod and push button partially depressed (Fig. 3) the notch 42 is in registry with opening 40 (Fig. 6) whereby the push button is illuminated. Thus, not only is a visual signal given, but also there is a touch signal provided because in running his hand across the panel, the control tower operator can feel the positions of the push buttons with respect to the top surface of the panel it).

As previously stated, actuation of the push button 38 causes the actual airport light which it represents, to be operated. Accordingly, subminiature switch 68 or an equivalent, is mounted on the casing 26 by suitable means, as bracket 7d, and it is operatively connected through other electrical means separated from panel 110, with the proper airfield light. A leaf spring 72 is fixed at one end to casing 26 and has a cam follower 74 at its opposite end passed through a casing wall opening and in contact with a cam 76 on the push rod 36. The shape of the cam is such that when the push button 33 is held in the partially depressed position (Fig. 3) the leaf spring 72 moves, by its inherent resilience, inwardly of casing 26. Switch 63 is so mounted that the leaf spring 72 touches its operator and therefore, is actuated in response to motion of the cam 76 over the cam follower '74.

In use, the control tower operator has many duties and occasions which will gave rise to his turning the airfield lights on and off. Thus, only one condition of operation will be assumed and that is that an airplane desires to land at night. The operator selects a landing strip and moves his hand down the runway on the panel, pressing the buttons thereon, in this way illuminating any lights necessary for the landing of the airplane.

What happens to each switch operating mechanism is that the button and push rod are urged into their casing against the yielding opposition of spring 34. At the same time switch 68 is actuated by the leaf spring '72-.which may be substituted by other equivalent elements such as a linkagedue to the cam 76 riding on cam follower 74. When the button is released, the ratchet prevents full return of the push rod and button, holding the button in such position that it accepts light rays through opening 40, thereby causing it to be illuminated.

After the airplane has landed and the tower operator decides to turn off the lights, he again presses the buttons 38 in the runway that has been used, releasing the ratchets of the switch operating mechanisms and allowing the springs 34 of each to return the push rods and buttons. Hence the openings 40 are blocked by a part of the push rods, preventing light rays from passing through the openings 46 and entering the push buttons 38.

It is understood that modifications as fall within the scope of the following claims may be made without departing from the protection afforded thereby.

What I claim is:

1. In a lighting facsimile map control panel system, a light transmissive control panel having a plurality of openings spaced at random therethrough; a tubular casing having a window in the wall thereof positioned transversely to said panel in each of said openings with said casing window opposite toand included by the wall of the panel opening; a switch slidably mounted in each casing comprising electrical contact elements, a push rod operatively connected to said elements for opening and closing the same, and a light conductive and un-shielded pushbutton connected to said rod and projecting externally from said panel and provided with a deflecting surface for transmitting light received through said window to the entire external and exposed area of said push-button; and single means for transmitting light through said panel only to the entire external area of each casing inside the panel opening as defined by a circumferential band including said window when said switch is closed.

2. The lighting facsimile map control panel system as defined in claim 1, with the push-button being partly contained in said casing and said deflecting surface comprising a reflecting side notch in the push-button wall adapted to register with said casing window when the switch contacts are in closed position.

3. In a lighting facsimile map control panel system, a light transmissive control panel having a plurality of openings spaced at random therethrough; a tubular casing having a window in the wall thereof positioned transversely to said panel in each of said openings with said casing window opposite to and included by the wall of the panel opening; a switch mounted adjacent each casing comprising electrical contact elements, a push rod operatively connected to said elements for opening and closing said con? tacts and said window, and a light conductive push-button connected to said push rod and projecting beyond the panel and adapted to transmit light from said window when said contacts are in closed position to the entire exposed area of said push-button; and single means for transmitting light through said panel only to the entire external area of each casing inside said panel opening as defined by a circumferential band including said window when said switch is closed.

References Cited in the file of this patent UNITED STATES PATENTS 2,038,093 Wight Apr. 21, 1936 2,441,614 Baumer May 18, 1948 2,607,874 Sheidler Aug. 19, 1952 2,609,476 Ackemann Sept. 2, 1952 2,699,141 Gaguski Jan. 11, 1955 

